In known collection apparatuses of the fraction collection type there is no synchronization of the switching of the receptacles, i.e. test tubes, with the emission of drops from the drip nozzle when collection is carried out by means of time-programmed switching. This leads to drops that appear in connection with a tube switching, occurring between the tubes which is disadvantageous, since, hereby, sample fluid is lost and at the same time the fraction collector is dirtied. Radioactive overflow would, moreover, be obtained in case the sample fluid would be radioactive.